1. Field of the Invention
The present invention relates to a non-linear analog signal conversion circuit configured of passive elements and a lighting apparatus using the same, the conversion circuit including: an input module for inputting a dimming signal; an inversion module for inverting the dimming signal; a non-linear conversion module for non-linearly converting input power Vdc into first output power Vo1 according to the inverted dimming signal; and a filter module for converting the first output power Vo1 of an output terminal of the non-linear conversion module into reference power Vref by removing noise of the first output power Vo1.
2. Description of Related Art
A light emitting diode (LED) is a kind of semiconductor device for converting electrical energy into light. The LED has advantages of low power consumption, semi-permanent lifespan, fast response time, safety and eco-friendliness compared with existing light sources such as a fluorescent lamp, an incandescent lamp and the like. Particularly, an LED lighting apparatus may carry out various performances by controlling the order of turning on and off LEDS installed in a plurality of arrays, colors and brightness of emitted light, and the like.
However, the load characteristic of a lighting unit using such an LED is shown to be non-linear with respect to linear constant voltage. Referring to FIG. 1, since a general dimming signal has a linear characteristic, a microprocessor (microcomputer) for processing the signal should be separately provided to control non-linear output using linear input.
Since the microprocessor for compensating the non-linear characteristic is implemented as a high-performance IC chip, a high-cost design is inevitable, and there exists a possibility of malfunction of software due to inflow of disturbance and noise.
Accordingly, measures for implementing an analog signal conversion circuit are studied in a variety of ways to utilize passive elements having a simple structure to the maximum instead of the microprocessor which controls using digital signals and to accomplish miniaturization and integration of a lighting apparatus.